Basic verification on measurement method of internal residual stress in polymers using THz polarization

Abstract

We proposed to utilize the response of the polymer to terahertz (THz) polarization as a non-destructive internal residual stress evaluation method for plastic molded products. PTFE samples with different residual stresses were manufactured and then the polarization dependence of the absorption coefficient was evaluated using THz time region spectroscopy. PTFE samples with lower residual stress showed almost no polarization dependence, whereas PTFE samples with higher residual stress showed large polarization dependence. In addition, we experimentally confirmed the correlation between THz polarization dependence and the dimensional change caused by residual stress. This paper revies the details about the principle and the verification.